Transverse distribution of critical current density in Ag-sheathed Ba1−xKxFe2As2 tapes. (26th November 2021)

• Record Type: Journal Article
• Authors: Yang, Peng; Huang, He; Han, Meng; Guo, Wenwen; Tu, Chang; Wang, Dongliang; Zhang, Xianping; Ma, Yanwei
• Is Part Of: Superconductor science & technology. Volume 35:Number 1(2022)
• Publication Date: 2021-11-26
• Subjects: Ba1−xKxFe2As2 tapes -- microstructure -- critical current density distribution -- inhomogeneity; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/ac39ea
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: The Ag-sheathed Ba1− x K x Fe2 As2 (Ba-122) monofilamentary tapes were prepared by the ex-situ powder-in-tube method. The variation of the microstructure and superconducting properties with the thickness of the superconducting core in the cross-section of sintered tapes is studied. At the same time, the reason is studied in comparison with the unsintered tapes. The research results show that the magnetic J c of the iron-based superconducting tapes increases continuously with distance from the core-sheath interface, which is the complete opposite of the Bi-based superconductor. The magnetic J c of central layers for final Ba-122 tapes is about 33% higher than the Jc of the whole tape at 4.2 K and 7 T. We have found that the center of the superconducting core shows higher hardness and better texture. In addition, it is also found that there is a reaction layer at the Ag-superconductor interface. These reasons may result in the reduction of the critical current density near the interface in the tapes. Moreover, we also found the presence of a reaction layer in the hot-pressed (HP) high-performance samples. However, no unevenness was found in the unsintered samples. Therefore, the superconductivity of Ba-122 tapes will be better by reducing the reaction layer and eliminating inhomogeneity at the core-sheath interface of the sintered tapes.